Bomper
Height: 66cm
Weight: 66kg
Speed: 66 km/hr
Bomper was created by Bowhale to support the Engines, he is a small Support Robot that supports the Go-onger in various circumstances with various equipment. Bomper also helps develop new tools to fight the Gaiark. Bomper is capable of jumping long distances. He hides in secret from others. He was kidnapped by Gunpei in episode 2. Bomper says his name is an anagram for "Born-to Outerdimension and Mechanic x Pitcrew-type ENGINE-support Robot."
Seji
He is a young popular flutist who was saved from Speaker Banki by Saki in Episode 6. Sousuke believed she was in love with him. He helped her point out a weakpoint in the monster. He appeared in Episode 6.
Fui Toujirou
Sousuke's former race car team supervisor. He was surprised by Sousuke's aburpt depature. He witness him and his team transforming to fight a monster. He clarifies to Sousuke in a moment where he was waiting for a miracle, that hard work and teamwork is what makes things work, not miracles. Appeared in Episode 8.
{Tree Spirit}
Not named, this seemingly lost boy once kept Saki company while lost in a forest ten years ago. She gave her strength by teaching her English word 'Smile' and stretching her cheeks, that she would carry with her and continue doing so. In current time, she thought he was a lost boy and protected him from a monster from the Samuari World. When she realized he was the same boy who kept her company those years ago, he shared his energy with her to defeat the monster. He later returned into himself, a tree. Appeared in Episode 24.
Retsu-Taka
His name means "Burning Falcon." He comes from the Samurai World. He is the leader of the Flame-People. First appeared in Engine Sentai Go-onger: Boom Boom! Bang Bang! GekijoBang!! They were the three Wandering Engines that came to the Samuari World and were robbed of their Engine Casts and hearts. He can become a Engine Soul and goes inside his Cast to become his true form. He put his soul in the Engine Sword, in order to keep the Dai-Shogun's power away from evil and entrusted it to two young brothers. In Episode 40, a man that resembles him stole the sword to activate Dai-Shogun. After rustling with Sosuke and moralizing, he came to his senses and saved the day.
Shishi-no-Shin
His name means "Moving Lion." He is an older warrior who wields a naginata. They were the three Wandering Engines that came to the Samuari World and were robbed of their Engine Casts and hearts. He can become a Engine Soul and goes inside his Cast to become his true form. He died in battle.
Tsuki-no-Wa
Her name means "Cresent Moon." She is the only female of the Flame-People. They were the three Wandering Engines that came to the Samuari World and were robbed of their Engine Casts and hearts. She can become a Engine Soul and goes inside his Cast to become his true form. She died in battle.
Osen
She pretended to be a grandmother who lived in a trash dump to Hanto and Hanto dressed up as her deceased granddaughter she made up. In reality, she is a tech-sorceress from Junk World, a Braneworld that resembles a junkyard due to Osen's invention that can multiply garbage. She was deceived by Kitaneidas into thinking that her own Braneworld was in danger from those from the Human World. She made a machine to give Gaiark the advantage, but after witnessing Hanto's kindness, Osen reverses her machine's polarity to covering everything with flowers, including the Gaiark. She then returned to her home dimension. Her name is from on the Japanese word for "pollution." She appeared in Episode 27.
Sakyou Kashiwagi
Sakyou is Gunpei's former partner, they were cops together and he is now a detective. Gunpei always boasted that he was a detective, but he was almost was there but quit to become a Go-Onger when the police refused to deal with the Gaiark. Sakyou investigated a Gaiark mystery and helped the Go-Onger out, telling Gunpherd to take care of his former partner. He appeared in Episode 28.
Sanae
Saki's 'devilish' elder sister who tortured her as a child and always sweeps in for money. Men, including the Go-Onger and the Engines, except for Gunpei, all fall head over heals for her. Gunpei didn't fall for her 'tricks' but one last new one fooled both Saki and Gunpei. Gunpei gave her the keys to Ginjiro Number One to take it to safety but she sold it and took the money, leaving town. She appeared in Episode 34.
Wameikle
Height: 60 cm to 210 cm
Weight: 6 kg to 130 kg
An infant-like tadole creature from the Stormy World, a Braneworld that is in a constant cycle of endless wind storms. When landing in Human World by accident, Wameikle's egg stuck in Hiroto's hull. He is found by Hiroto, with him seeing him as a parent. However, the Ugats are sent after him to force grow jim into a berserker adult and utilize its high-pitch sonic scream to tear down the dimenional barrier that separates the Stormy World and Human World. Its name is from on the Japanese word for "cry." He reverted back to his nice self, but still adult by a special device created by Renn, Saki, and Miu ultilized by Hiroto. He floats back to his world.